LABORATORY WORK #5
DEFINITION OF STEFAN-BOLTZMANN CONSTANT
PhysicVirtualLab Software Package
Figure 4 - The calibration curve
Procedure:
3.1By clicking on the Laboratory work you can get window with slider. Please choose number of experiments from 3 to 10.
3.2At the left scheme (source of lamp L1) choose one of certain value for voltage from 8 to 12 V. Using the horizontal slider for R, set up working
current of the lamp L1, which define background brightness of filament’s image.
3.3Values for current Iп can be measured with accurate precision, because changing of R in the circuit of pyrometer using vertical slider on the right scheme allow us to get bright or dark curved image of filament of standard lamp. It gives us possibility to obtain fully disappearance of the working part
of lamp L2 on the background of lamp L1. Please input all data into the Table 1.
PhysicVirtualLabs Project Team, IITU
Copyright 2014
LABORATORY WORK #5
DEFINITION OF STEFAN-BOLTZMANN CONSTANT
PhysicVirtualLab Software Package
Table 1
S |
I |
U |
Iп |
T, °C |
T, K |
σ |
<σ> |
Δσ |
ε, % |
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3.4Repeat measurements of pyrometer are current by changing R every time. If you finish measurements, please click the button and you will get table with all parameters and measured data. You can check your data with data of the application.
3.5Using the working formula please define the Stefan’s constant. Make error analyses using the Student’s method.
3.6Discuss your results and the reasons of the uncertainties.
S |
I |
U |
I2 |
T, °C |
T, K |
σ |
<σ> |
Δσ |
ε, % |
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4.QUESTIONS:
4.1Give the main definitions of the thermal radiation.
4.2How is the integral and spectral emissivity of a body connected?
4.3What is a black body? What kind of bodies can be seen as absolute black?
4.4Formulate the basic laws of thermal radiation.
4.5What is and how has been defined the "ultraviolet catastrophe"?
4.6What is the physical meaning of Planck's formula?
4.7How does a disappearing filament pyrometer work? What is the brightness temperature measurement method?
PhysicVirtualLabs Project Team, IITU
Copyright 2014
LABORATORY WORK #5
DEFINITION OF STEFAN-BOLTZMANN CONSTANT
PhysicVirtualLab Software Package
5.REFERENCES:
5.1Raymond A. Serway, John W. Jewett Physics for Scientists and Engineers with Modern Physics. Eighth edition. 2010.
5.2T.I. Trofimova «General physics» Moscow, Vyschaya schkola, 2001.
5.3I.V. Savelyev. «Course of general physics». V.3, M.: «Nauka». 1977.
PhysicVirtualLabs Project Team, IITU
Copyright 2014